Contrary to prevailing medical opinion, low dose aspirin therapy during pregnancy does not prevent preeclampsia in women who are at high risk for the disease, according to the largest, most comprehensive study of its kind.

Preeclampsia is a disorder of pregnancy that can strike without warning, causing high blood pressure and protein in the urine. In turn, preeclampsia may progress to eclampsia--hypertension and generalized convulsions--which may be fatal.

The trial, reported in the March 12 New England Journal of Medicine, was conducted by researchers at the National Institute of Child Health and Human Development (NICHD) Network of Maternal-Fetal Medicine Units, a network of 13 clinical research centers studying various aspects of maternal-fetal medicine.

"Women at high risk of preeclampsia should not be given aspirin therapy to prevent the condition, as our study shows it doesn't work." said Dr. Donald McNellis, the NICHD project officer for the study and an author of the paper. "Although our study did not find any ill effects from the aspirin, this drug does have known potential side effects."

Side effects of aspirin include irritation of the stomach and intestine and spontaneous hemorrhaging. During pregnancy, aspirin may increase the risk for abruptio placentae--separation of the placenta from the uterine wall at birth.

The authors note that preeclampsia is a leading cause of maternal death. About 5 percent of first-time mothers and 1 to 2 percent of mothers having subsequent pregnancies develop the condition. Even in cases where the condition does not progress to eclampsia, the children born to mothers with preeclampsia may be small for their gestational age or may be born prematurely; this may, in turn, place them at risk for a variety of other complication.

Although the high blood pressure accompanying preeclampsia can be treated with blood pressure lowering drugs,
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Contact: Bob Bock
rb96@nih.gov
301-496-5133
NIH/National Institute of Child Health and Human Development
11-Mar-1998